Why Empty/ Image is freezing Blender (2.77a)?
If selecting objects takes too long , change the selection method :
in user preferences under system tab , change selection mode to OpenGL Occlusion Queries.  



if it's still slow , give the empties meaningful names and select them from the outliner instead.  

The shortcut  ALTRMB will pop up a menu in the 3d view with a list of object names directly under the cursor,It should saves you the trouble of going back and forth between the two panels.